modular_matrix: don't use STL iterators in {mul, sub}_col and friends.
authorAlexei Sheplyakov <varg@metalica.kh.ua>
Sat, 8 Aug 2009 10:03:15 +0000 (13:03 +0300)
committerJens Vollinga <jensv@nikhef.nl>
Sun, 9 Aug 2009 21:41:21 +0000 (23:41 +0200)
Not using STL iterators makes the code simpler and cleaner. Also we don't
have to argue whether the standard ([lib.random.access.iterators]) imposes
any pre/post-condictions on operator+=.

ginac/factor.cpp

index 2f9157b..c82e744 100644 (file)
@@ -691,90 +691,76 @@ public:
        cl_MI operator()(size_t row, size_t col) const { return m[row*c + col]; }
        void mul_col(size_t col, const cl_MI x)
        {
-               mvec::iterator i = m.begin() + col;
                for ( size_t rc=0; rc<r; ++rc ) {
-                       *i = *i * x;
-                       i += c;
+                       std::size_t i = c*rc + col;
+                       m[i] = m[i] * x;
                }
        }
        void sub_col(size_t col1, size_t col2, const cl_MI fac)
        {
-               mvec::iterator i1 = m.begin() + col1;
-               mvec::iterator i2 = m.begin() + col2;
                for ( size_t rc=0; rc<r; ++rc ) {
-                       *i1 = *i1 - *i2 * fac;
-                       i1 += c;
-                       i2 += c;
+                       std::size_t i1 = col1 + c*rc;
+                       std::size_t i2 = col2 + c*rc;
+                       m[i1] = m[i1] - m[i2]*fac;
                }
        }
        void switch_col(size_t col1, size_t col2)
        {
-               cl_MI buf;
-               mvec::iterator i1 = m.begin() + col1;
-               mvec::iterator i2 = m.begin() + col2;
                for ( size_t rc=0; rc<r; ++rc ) {
-                       buf = *i1; *i1 = *i2; *i2 = buf;
-                       i1 += c;
-                       i2 += c;
+                       std::size_t i1 = col1 + rc*c;
+                       std::size_t i2 = col2 + rc*c;
+                       std::swap(m[i1], m[i2]);
                }
        }
        void mul_row(size_t row, const cl_MI x)
        {
-               vector<cl_MI>::iterator i = m.begin() + row*c;
                for ( size_t cc=0; cc<c; ++cc ) {
-                       *i = *i * x;
-                       ++i;
+                       std::size_t i = row*c + cc; 
+                       m[i] = m[i] * x;
                }
        }
        void sub_row(size_t row1, size_t row2, const cl_MI fac)
        {
-               vector<cl_MI>::iterator i1 = m.begin() + row1*c;
-               vector<cl_MI>::iterator i2 = m.begin() + row2*c;
                for ( size_t cc=0; cc<c; ++cc ) {
-                       *i1 = *i1 - *i2 * fac;
-                       ++i1;
-                       ++i2;
+                       std::size_t i1 = row1*c + cc;
+                       std::size_t i2 = row2*c + cc;
+                       m[i1] = m[i1] - m[i2]*fac;
                }
        }
        void switch_row(size_t row1, size_t row2)
        {
-               cl_MI buf;
-               vector<cl_MI>::iterator i1 = m.begin() + row1*c;
-               vector<cl_MI>::iterator i2 = m.begin() + row2*c;
                for ( size_t cc=0; cc<c; ++cc ) {
-                       buf = *i1; *i1 = *i2; *i2 = buf;
-                       ++i1;
-                       ++i2;
+                       std::size_t i1 = row1*c + cc;
+                       std::size_t i2 = row2*c + cc;
+                       std::swap(m[i1], m[i2]);
                }
        }
        bool is_col_zero(size_t col) const
        {
                mvec::const_iterator i = m.begin() + col;
                for ( size_t rr=0; rr<r; ++rr ) {
-                       if ( !zerop(*i) ) {
+                       std::size_t i = col + rr*c;
+                       if ( !zerop(m[i]) ) {
                                return false;
                        }
-                       i += c;
                }
                return true;
        }
        bool is_row_zero(size_t row) const
        {
-               mvec::const_iterator i = m.begin() + row*c;
                for ( size_t cc=0; cc<c; ++cc ) {
-                       if ( !zerop(*i) ) {
+                       std::size_t i = row*c + cc;
+                       if ( !zerop(m[i]) ) {
                                return false;
                        }
-                       ++i;
                }
                return true;
        }
        void set_row(size_t row, const vector<cl_MI>& newrow)
        {
-               mvec::iterator i1 = m.begin() + row*c;
-               mvec::const_iterator i2 = newrow.begin(), end = newrow.end();
-               for ( ; i2 != end; ++i1, ++i2 ) {
-                       *i1 = *i2;
+               for (std::size_t i2 = 0; i2 < newrow.size(); ++i2) {
+                       std::size_t i1 = row*c + i2;
+                       m[i1] = newrow[i2];
                }
        }
        mvec::const_iterator row_begin(size_t row) const { return m.begin()+row*c; }